Priority is claimed to Korean Patent Application No. 10-2004-0048665, filed on Jun. 26, 2004, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to a method for analyzing an organic light-emitting device (OLED), and more particularly, to a method for analyzing the performance of an OLED through activation in-situ.
2. Description of the Related Art
OLEDs are a common type of display device, which use organic compounds to emit light without external illumination. OLEDs have a simpler structure and are easier to manufacture than thin film transistor liquid crystal displays (TFT LCDs). That is, OLEDs have lower production costs, and have just one half the power consumption and one third the thickness of TFT LCDs, while having a response rate 1000 times faster. Thus, OLEDs are used in moving picture applications, such as mobile phones, PDAs, etc.
However, OLEDs have the problems of short lifetime and low efficiency. Research into overcoming these problems is hampered by a lack of techniques for analyzing OLEDs, due to their organic thin film multi-layered structure. Furthermore, in a conventional estimation method, when the characteristics of OLEDs are estimated ex-situ while being driven, the OLEDs are sensitive to the external environment, making estimation unreliable.
Conventional methods of analyzing OLEDs comprise ex-situ estimating the characteristics of the devices using conventional surface analysis apparatus, such as X-ray photoelectron spectroscopy (XPS), Ultraviolet Photoemission Spectroscopy (UPS), Raman, or Scanning Electron Microscopy (SEM), etc.
In these cases, oxygen and moisture contacts the devices causing direct thermal degradation in less than one second. Thus, when using the above conventional surface analysis apparatus ex-situ, it is difficult to analyze dark spots which are responsible for the degradation and shortened lifetime of OLEDs.
To prevent oxygen and moisture from reaching the devices, there is a need for in-situ analysis.
Referring to FIG. 1, the conventional method of analyzing OLEDs is performed under two conditions. Finding a dark spot (I) is performed ex-situ and analyzing the dark spot (II) is performed in-situ. In the process 1, an OLED to be analyzed is placed on an ex-situ analysis apparatus (S10) and a bias voltage is applied to the OLED (S20). At this time, a dark spot is found in the OLED (S30). Then, the area of the OLED to be analyzed is marked (S40) and the process 11 is performed.
In the process 11 of in-situ analysis, firstly the OLED with the marked area is placed in the chamber of an analyzer (S50). Then, scanning is performed through the OLED (S60) and the marked area is found (S70), repeating these operations (S60 and S70). If the marked area is found, the marked area is scanned with a focused beam (S80), to obtain local chemical information on the marked area (S90), and then the analytical results are output (S95).
As described above, when the manufactured OLED is again placed in the analyzer for in-situ analysis, it is difficult to set the position of the dark point in the analyzer, since the dark spot is small. Further, the dark spot can be confused with a defect caused by careless surface treatment of the OLED, and the OLED degrades very rapidly during ex-situ analysis, making practical analysis difficult. Moreover, since degradation of the OLED occurs very rapidly during ex-situ analysis, it has a practical difficulty in analysis for such degradation.